César-François Cassini de Thuryni

César-François Cassini de Thury (17 June 1714 – 4 September 1784), also called Cassini III or Cassini de Thury, was a French astronomer and cartographer.

Biography

Cassini de Thury was born in Thury-sous-Clermont (Oise), the second son of Jacques Cassini and Suzanne Françoise Charpentier de Charmois. He was a grandson of Giovanni Domenico Cassini, and would become the father of Jean-Dominique Cassini, Conte de Cassini.

In 1735, he became a member of the French Academy of Sciences as a supernumerary adjunct astronomer, in 1741 as an adjunct astronomer, and in 1745 as a full member astronomer.

He succeeded to his father’s official position in 1756 and continued the hereditary surveying operations. In 1744, he began the construction of a great topographical map of France, one of the landmarks in the history of cartography.[1]

The post of director of the Paris observatory was created for his benefit in 1771 when the establishment ceased to be a dependency of the French Academy of Sciences.

His chief works are: La méridienne de l’Observatoire Royal de Paris (1744), Description géometrique de la terre (1775), and Description géometrique de la France (1784), which was completed by his son.

César-François Cassini de Thury died of smallpox in Paris on 4 September 1784,